1. Field of the Invention
This invention relates to oil compositions comprising crude oils, mineral oils, fuel oils and synthetic oils having one or more improved characteristics, such as pour point, viscosity, viscosity index, flowability and the like.
Crude, refined and synthetic oils frequently require modification or the addition of additives to improve one or more of their physical characteristics, such as, pour point, viscosity, viscosity index, etc. In particular, one more more of the above-described properties is imparted to oil compositions by the addition thereto of copolymers comprising an alkyl amine or alkyl mercaptan derivative of an alpha olefin or an alkyl vinyl ether and maleic anhydride. The copending application of Hanh T. Le, entitled "Alkyl Amine or Alkyl Mercaptan Derivatives Of An Alpha Olefin Or Alkyl Vinyl Ether And An Alpha, Beta-Dicarboxylic Compound", Ser. No. 265,611, filed Oct. 31, 1988, describes in detail how to prepare these compounds.
Crude oils, depending upon the location of production may contain substantial quantities of wax. This wax is subject to separation when the crude oil is cooled below the pour point index of the oil. Crystallized wax precipitates from crude oil at sufficiently low temperatures and the oil, as well, can completely solidify causing reducing flowability and or pumpability of the oil.
When crude oil is produced from a production well through strata having lower temperatures tha that of the oil-bearing formations, the crude oil may gel or transform into a dense or glutinous consistency, which can interfere with its transfer to the surface. The problem of crude oil and oil compositions solidifying, especially during extreme weather conditions is further emphasized during the storage of the oil in tanks which do not have insulation or heating facilities or in transporting the oil in unheated tankers or through a pipeline.
Thus, acceptable pour points and flow characteristics of an oil composition are highly desirable, particularly during production and upon storage, and transport of the oil composition; and especially during a refining operation when the oil composition is a crude oil. It should be noted that the copolymers herein, when incorporated in an oil composition, substantially lower the pour point and concomitantly enhance the flowability of the oil composition.
2. Description of the Prior Art
Processes and catalysts for the production of polymers and copolymers of organic compositions as oil additives are known and are currently practiced commercially.
For example, U.S. Pat. No. 3,677,725 relates to copolymers of (1) maleic anhydride and an alpha olefin or an alkylvinylether and (2) alkyl esters of carboxymethyl amides or carboxymethyl esters of maleic anhydride, alpha olefins or alkylvinylethers. These copolymers are described as useful for imparting antistatic properties to distillate fuel oils and other volatile liquid compositions.
U.S. Pat. No. 3,694,176 discloses copolymers of ethylene and an alpha-beta ethylenically unsaturated dicarboxylic acid or its anhydride or mono- or diester. The copolymers are described as suitable for use as wax crystal modifiers. pour point depressants and dewaxing aids for hydrocarbon oils.
U.S. Pat. No. 3,776,247 relates to a composition of matter having improved flow and friction-reducing properties which consists of a waxy crude oil containing a polymer selected from copolymers of anhydrides of dicarboxylic acids and mono-olefins or alkylvinylether copolymerized with the dialkylester of an unsaturated acid.
U.S. Pat. No. 3,879,177 discloses a process for inhibiting the crystallization of wax from a waxy crude oil produced from a subterranean formation by adding to the waxy oil a copolymer of maleic anhydride and vinylmethyl ether esterified with an alcohol containing 18 to 24 carbon atoms.
U.S. Pat. No. 4,240,916 relates to lubricating oil compositions having enhanced pour point depressant properties. Copolymers of maleic anhydride and alpha olefins are described as suitable for use in the oil compositions.
As can readily be determined from the above, there is an ongoing search for newer and more effective polymers and copolymers for use as pour point depressants in oil compositions. It should be noted, however, that the specific amine or mercaptan derivatives of the copolymers herein are new.